Magnetic characterization of diluted magnetic semiconductor thin films

Abstract

In studies of weak magnetism in diluted magnetic semiconductor thin films, there is often a significant difficulty in subtracting the background signal arising from the substrate. In the present work, an improved magnetic correction method is proposed. For Al doped ZnO and Fe doped TiO2 films, the magnetic moment and coercivity of the samples were corrected by the improved method, and the maximum fitting error due to the glass substrate was calculated. The accuracy and rationale of the improved method are discussed and compared with the traditional method. The results show that room temperature ferromagnetism is observed in Fe doped TiO2 thin films. The ferromagnetism is strongly correlated with the substitution of Ti by Fe in the TiO2 lattice, which results in a change in the crystal structure and the quality of the crystallization of the TiO2 films. The changes are responsible for altering ferromagnetism in the films.

Significant room-temperature ferromagnetism in porous ZnO films: The role of oxygen vacancies

“…The highest magnetization (∼110 emu/cm 3 ) was observed for the thinnest film. Such high saturation magnetization is large enough to eliminate the doubt that the observed magnetism is due to magnetic contaminants in otherwise nonmagnetic films [27]. Compared to other films, there is the largest surface/volume ratio in the porous film of 5 min, since the pore diameters are larger than the films produced with longer sputtering times as may be seen from the SEM images, while the thickness is thinner than the others.…”

“…Fig. 3 shows the corrected in-plane and out-of-plane magnetization curves, where the diamagnetic background has been removed [27]. The inset of Fig.…”

Unexpected large room-temperature ferromagnetism in porous Cu2O thin films

“…Such a high saturation magnetization is large enough to eliminate any doubt that the magnetism in this film is predominantly due to magnetic contaminants, such as Fe ions (Ref. [27]). In addition, one can see that the saturation magnetization decreases rapidly in the out-of-plane direction and increases slowly in the in-plane direction as the sputtering time increases.…”

Voltage-Driven Room-Temperature Resistance and Magnetization Switching in Ceramic TiO2/PAA Nanoporous Composite Films

“…Previous works have proved that the physical properties of metal oxides are influenced by the oxygen vacancies. ,, To examine the relationship between oxygen vacancy concentration and magnetism, the room-temperature magnetic moment versus magnetic field ( M – H ) curves with the magnetic field perpendicular to the TP film plane and PL spectra under different conditions were measured, as shown in Figure . As shown in Figure a, we draw the hysteresis loops using raw data in order to eliminate the correction error. , The well-defined hysteresis loops of the samples exhibit the RTFM nature of the TP films. In general, heat treating the oxide in reducing atmosphere (or vacuum) will increase the oxygen vacancy concentration.…”